The invention relates to radio wave antennas and directive radio wave systems and devices, and more particularly to a compact electromagnetic antenna that can be used in conformity with a variety of surfaces and supports wideband signaling.
At present there is a broad class of antennas whose members support wideband signaling. For purposes of this application, the term xe2x80x9cwidebandxe2x80x9d is intended to mean signals that have bandwidths several tens of percent of the center frequency of the communications. There are also narrowband antennas whose physical envelope characteristics require only very small volumes and areas, and can be conformally placed on surfaces of gradual contours. A class of such antennas is known in the art as patch antennas or microstrip antennas.
Patch antennas are a subset of resonant antennas and therefore are capable of signaling over only a small bandwidth, on the order of a few percent of center frequency. This behavior is discussed by Professors Stutzman and Thiele in the second edition of their text Antenna Theory and Design, John Wiley and Sons 1998. The main challenge in microstrip antenna design is thus to achieve a wider signaling bandwidth.
Currently, there are several communication systems in development that propose to employ very wideband signaling. Many of these desired systems will require, or would greatly benefit from, a small volume conformal antenna. There is therefore a recognized need for a patch antenna that is capable of handling wideband signaling.
Briefly, in accordance with a preferred embodiment of the invention, two essentially identical electrically conducting rectangular plates are provided, with their surfaces separated and lying in parallel planes. A frequency dependent dielectric is situated between the plates and electrical conductors are connected to the plates, thus forming a patch antenna that is resonant over a wideband frequency range and is consequently capable of radiating and receiving a wideband signal.